The invention relates to a positioning device comprising a table, which is displaceable in at least two coordinate directions (X, Y) by means of at least one electric linear X-motor and at least one electric linear Y-motor and is supported without contact by a static gas bearing on a base, coil systems and magnet systems corresponding to the two motors being connected to the base and to the table, respectively.
In a positioning device of the kind mentioned in the opening paragraph above, known from European Patent Application EP-A1-0244012, the coil systems and magnet systems of the electric linear motors both for the X-coordinate direction and for the Y-coordinate direction are coupled and guided not only by electromagnetic Lorentz forces, but also by guide rollers, of which a few are displaceable in a direction transverse to their axis of rotation under the force of a spring. The last-mentioned fully mechanical coupling and guiding has the disadvantage that owing to the friction of the rollers in a controlled system a comparatively small bandwidth is attainable and the accuracy of the positioning device is limited.